A Cochrane review [Abstract] 1 included 8 studies with a total of 938 patients with dementia. Six trials did not specify the type of dementia, one specified Alzheimer's disease and one vascular dementia. One trial had 610 patients, the rest were small. The mean age of subjects was in the range 72.5 to 80.0 years. Three trials compared thioridazine with diazepam and one of these had a placebo group. Of the remaining trials one compared thioridazine with loxapine and placebo, one with loxapine, one with zuclopenthixol, one with etoperidone and one with chlormethiazole. The given mean doses of thioridazine ranged from 32.9 to 95 mg. All the trials were of short duration, six lasted 3 to 4 weeks and two 8 weeks. Several scales for behavioral rating, clinical global assessment, cognitive or functional performance were used. Adverse events were not reported in any systematic manner in any of the trials.
• Thioridazine compared with placebo (2 trials, n=670): there was a reduction in anxiety symptoms by changes on the Hamilton Anxiety Scale (OR 4.91; 95% CI 3.21 to 7.50). However, there was no significant effect on clinical global change (OR 1.58; 95% CI 0.42 to 5.96), and a non-significant trend for higher adverse effects with thioridazine. • Thioridazine compared to diazepam (3 trials, n=729): thioridazine was superior only in one study that combined items intellect/agitation/depressed mood/behaviour at interview (OR 1.80; 95% CI 1.04 to 3.10), with similar adverse effects. Global clinical evaluation scales did not favour either treatment.
• Thioridazine compared to chlormethiazole (1 trial, n=74): thioridazine was significantly inferior when assessed on nocturnal confusion item of the Clifton Assessment Procedures for the Elderly (CAPE) (OR 0.24; 95% CI 0.09 to 0.69) and the Crichton Geriatric Behavioural Rating Scales for items confusion/alertness (OR 0.31; 95% CI 0.11 to 0.89). Thioridazine was associated with significantly more dizziness (OR 0.18; 95% CI 0.04 to 0.80).
• Thioridazine in comparisons with etoperidone (1 trial, n=30), loxapine (2 trials, n=101) or zuclopenthixol (1 trial, n=64): No superiority for thioridazine was shown, except to produce fewer side effects than loxapine.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment), inconsistency (heterogeneity in populations, comparators and outcomes) and imprecise results (small studies with wide confidence intervals).
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